Swiss patent 557 423 describes 3-mercapto carboxylic esters of the general formula I
wherein R1 represents an alkyl or alkenyl or alkadienyl group with 1 to 6 carbon atoms, and R2 represents an alkyl or alkenyl group containing 3 to 9 carbon atoms. These 3-mercapto carboxylic esters are known as flavor or fragrance compounds, and possess either green organoleptic properties, e.g. leaf green (3-mercapto-4-methylhexanoic acid ethyl ester), green fruity (3-mercapto-4-methylhexanoic acid hex-3-enyl ester), green and pungent (3-mercapto-4-methylhexanoic acid 2-hexenyl ester), or fatty organoleptic properties (e.g. 3-mercaptooctanoic acid ethyl ester, 3-mercaptononanoic acid methyl ester, 3-mercaptodecanoic acid ethyl ester or 3-mercapto-4-ethylhexanoic acid ethyl ester). An exception is 3-mercapto-4-methylhexanoic acid hexa-2,4-dienyl ester with a sulfurous, onion and garlic-like note. The latter-mentioned compound demonstrates that a small change in the structure of the compound can cause a dramatic change of the odor properties; e.g. a hexa-2,4-dienyl group instead of a hex-3-enyl group changes the organoleptic character from green-fruity to onion, garlic-like.
The flavor and fragrance industry is further interested in new ingredients with a clear fruity character. Thus, the above mentioned compounds would be of interest if they do not have the disadvantage that the fruity note is always combined with green and/or fatty notes.